Office chairs having side arms have conventionally employed a multiple post arrangement for mounting the side arm. This multiple post arrangement has generally been secured to structure disposed internally of the seat, with the multiple posts projecting outwardly from the side of the seat and upwardly for attachment to the side arm adjacent the front and rear ends thereof. This multiple post arrangement was generally considered necessary in order to provide the side arm with adequate strength, particularly so as to be capable of withstanding the substantial downwardly and sidewardly directed loads as imposed on the arm during use of the chair. While this type of side arm arrangement does normally provide adequate strength and durability, nevertheless it also greatly restricts the esthetics and design characteristics of the chair.
In an attempt to provide a chair having a substantially different appearance, several office chairs have been designed utilizing cantilevered side arms. That is, the front end of the arm is not supported, so that the side arm is fixedly supported in its entirety solely by fixedly anchoring the rear end of the arm to suitable structure stationarily associated with the chair. This thus makes it extremely difficult to provide a strong and secure mounting of the cantilevered side arm, particularly since the side arm must be capable of withstanding minimum loading standards relative to downward vertical loads and outward sidewardly directed loads. Providing a proper structural mounting of the cantilevered arm so as to comply with, or exceed, the minimum loading requirements has thus presented a substantial obstacle and, in many instances, has required that the design (that is, the esthetics) of the arm be modified or that complex and costly structures be utilized.
Accordingly, this invention relates to an office chair having side arms, specifically cantilevered side arms, and the purpose of this invention is to provide an improved mounting arrangement for the cantilevered side arms so as to provide the side arms with substantial strength and rigidity whereby the side arms are capable of withstanding imposition thereon of external loads of substantial magnitude when imposed vertically downwardly and horizontally outwardly sidewardly thereof, while at the same time this improved mounting arrangement does not interfere with the ornamental and design characteristics of the cantilevered arms and of the overall chair. The improved arm mounting arrangement of this invention also enables the cantilevered arms and mounting structure to be manufactured and assembled with minimal complexities so as to permit efficient and economical manufacture.
In the chair of this invention, each cantilevered side arm includes an arm rest portion which at its rearward end terminates in an intermediate arm portion which is of compound curvature in that it projects rearwardly, curves downwardly, and also curves inwardly so as to terminate in a base portion which is positioned adjacent the rear edge of the seat. This base portion has an armlike mounting portion integral therewith and projecting forwardly therefrom into the interior of the seat. This armlike mounting portion is cantilevered from the base portion. The mounting structure for the cantilevered arms includes a U-shaped tubular frame which is positioned within the interior of the seat so that the legs of the U-shaped frame project forwardly of the seat, and the bight of the U-shaped frame is positioned adjacent the rearward edge of the seat. The legs of the U-shaped frame are fixedly secured, as by screws, to the conventional chair-control frame as disposed interiorly of the seat. The rear portion of the U-shaped frame, including the bight and the curved elbows which join the bight to the legs, is disposed within a plane which is inclined upwardly and rearwardly relative to the legs, such as at an angle of approximately 30.degree.. The armlike mounting portions, as they project forwardly into the chair seat, are also inclined downwardly at a similar angle. An upwardly opening, channel-like bracket is fixedly secured to each of the elbows, and is inclined at the same angle as the elbow. Each bracket fixedly and snugly receives therein the armlike mounting portion. The mounting portion, bracket and U-shaped frame are suitably fixedly connected by threaded fasteners.
The cantilevered arm mounting arrangement of this invention is such as to be cost effective, relative to both labor and materials. Further, this arrangement is capable of meeting industry standards by means of a structure which, when subjected to minimal loading requirements, does not provide any plastic yield or permanent deformation, while at the same time utilizing a simple connecting structure which requires only minimal tooling and which does not interfere with the shape or size or comfort of the chair seat.
Other objects and purposes of the invention will be apparent to persons familiar with chairs of this type upon reading the following specification and inspecting the accompanying drawings.